Absorbent article having improved bonding pattern

ABSTRACT

The present invention relates to improvements in bonding patterns for the attachment of components of disposable absorbent articles. For example, in order to provide attachment of an ear portion to a longitudinal side of the chassis of an article, there may be an attachment area The attachment area may include an overlapping area of chassis material(s) (outer cover and/or liner materials) and ear portion material. The over-lapping areas of chassis material and ear portion material are bonded together in such a way as to allow the bond pattern area to stretch from 8% to 30%. The bonding patterns of the invention may also be used to form the side seams and passive side bonds for articles that are donned as pants.

This patent application is a non-provisional patent application claimingpriority to U.S. provisional patent application serial No. 60/405861filed on Aug. 22, 2002.

BACKGROUND OF THE INVENTION

The present invention is generally related to the assembly of componentsof disposable absorbent articles. The present invention also relates tothe attachment of components such as ear portions to the main portion orchassis of a disposable absorbent article. Additionally, the presentinvention relates to bonding patterns that increase the durability andintegrity with which components are attached to disposable absorbentarticles.

Disposable absorbent articles have been known for a long time aspersonal care hygiene products. Disposable absorbent articles includeinfant diapers, is diaper pants, toddler training pants, swim pants,adult incontinence pads and briefs and women's sanitary pads. Suchabsorbent articles are designed and constructed to absorb and storesolid and liquid bodily excretions such as urine, feces, menstrualfluid, or blood.

Nonwoven materials may be used extensively for the construction ofdisposable absorbent articles. Frequently, disposable absorbent articlesare constructed of multiple nonwoven material components. For example, adisposable absorbent article may include a bodyside liner (also known asa topsheet) that contacts the wearer's skin in use, an absorbent coreand an outer cover (also known as a backsheet) that is typically liquidimpermeable. These three components run generally continuously with eachother and together form what may be referred to as the “chassis” of thearticle. In addition, disposable absorbent articles may includecomponents such as leg elastics, waist elastics, containment flaps,front waist ear portions, back waist ear portions and fastening systemsfor improving the fit and containment of the articles. These types ofcomponents are generally incorporated into the articles by attachingthem to the chassis of the article. For example, the front waist earportions and back waist ear portions may be attached to the chassisduring manufacture.

The components of the disposable absorbent article used to secure thearticle to the intended wearer (e.g. ear portions and fasteners) tend toexperience a significant concentration of stress during application ofthe article. If the concentration of stress exceeds the strength of thematerial, the components may become partially or completely detachedfrom the article. The concentration of stress may be increased inregions or areas where multiple layers of materials are bonded together.An example of an area that may be subjected to increased stress forcesduring use of the article is the area where the back ear portions areattached to the back waist region of the chassis. Typically, earportions are attached to the chassis of an article near the waist edgeand along the longitudinal side edge of an article. With this example,the back ear portion will include at least one layer of nonwovenmaterial that may be attached to at least the bodyside liner or theouter cover materials of the chassis. One way that the back ear portionmay be attached to the chassis is by ultrasonic bonding. Prematurefailure at the attachment area, either where components are attached tothe chassis or where components are attached to one another, may cause anegative impact on product appearance and/or product performance. Forexample, if the attachment of the fasteners fails, the article may notfit as intended. Poor fit may lead to a decrease in effectiveness of theabsorbent ability of the article, potentially resulting in prematureleakage. Additionally, it is desirable to attach components in such away that the overall integrity (i.e. no loose or missing pieces) of thearticles is preserved.

Various techniques are available for attaching components to the chassisand for attaching components to one another. Traditionally, adhesiveapplication was the predominant technique for attaching components. Morerecently, adhesive application has been replaced by molecular bondingwith ultrasonic bonding representing one specific method of molecularbonding. In very simplified terms, ultrasonic bonding involves thevibration of a “horn” device at ultrasonic frequencies which, incombination with an “anvil”, causes localized heating and bonding ofsubstrate material(s) positioned between the horn and the anvil. Thislocalized heating and bonding forms a bond element when a raisedprojection is provided on either the horn or the anvil. The raisedprojection forms an individual bond element in approximately the shapeof the raised projection, and leaves the surrounding material relativelyunchanged. Representative examples of rotary ultrasonic horns which havebeen used to bond at least one component are described in U.S. Pat. No.5,096,532 to Neuwirth et al. on Mar. 17, 1992 and U.S. Pat. No.5,110,403 issued to Ehlert on May 5, 1992. A representative example of arotary ultrasonic bonding apparatus is described in U.S. Pat. No.6,537,401 issued to Couillard et al. on Mar. 25, 2003. A problem withcurrent rotary ultrasonic bond patterns is “chatter” or “bounce” whichresults when a smooth horn is pressed against a patterned anvil. This“bounce” may cause wear of the anvil, horn or support structure of therotary ultrasonic device. This wear can potentially cause wear andincreased variability in bonding effectiveness.

The individual bond elements may be in the form of straight or curvedlines, geometric shapes such as circles, squares, rectangles, diamonds,and similar shapes or irregular shapes. A bond pattern is formed whenthe bond element is one of a group of one or more bond elements spacedin relative proximity to each other. The bond pattern may be formed byindividual bond elements arranged in a linear or nonlinearconfiguration. Such patterns may be located on the bonding horn or theanvil roll. However, the pattern is traditionally located on the anvilroll for improved manufacturing efficiency. Various ultrasonic bondpatterns may be achieved through arrangement of appropriate raisedprojections on an anvil.

Conventional ultrasonic bond patterns have positioned adjacent bondelements in uniform straight lines and crossing rows for manufacturingefficiency. The design of these conventional bond patterns has evolvedas a replacement for adhesive bonding. As the number and type ofcomponents increases and as new component materials become available,presently available bond patterns may not be optimal.

Adhesive bonding usually causes little or no damage to the materialsbeing bonded together, and therefore, from a bond strength perspective,more adhesive per length or area is generally better. Due to the energyassociated with forming ultrasonic bonds, ultrasonic bonding may weakenor damage materials. Therefore, in contrast, more ultrasonic bonding perlength or area may cause degradation of the materials being bondedtogether if the ultrasonic bonds are too dense or too great in number.As a result, presently available bond patterns may not providesufficient attachment strength.

Desirably, materials that are bonded together overlap minimally. Minimaloverlap reduces raw material cost, as well as improves the aesthetics ofthe finished product. Minimal overlap is also beneficial when bondingstretchable components together because conventional bonding techniques(adhesive and ultrasonic) may tie up or prevent the material within thebond area from stretching as much as the unbonded material.

Adhesive bonding, unlike ultrasonic bonding, has the additional problemof overspray. Overspray occurs when misapplied adhesive is not containedbetween two components. This misapplied adhesive may then causeprocessing and product problems. The misapplied adhesive may cause theproduct, or other materials, to adhere to parts of the processingmachine potentially resulting in a jam. The misplaced adhesive may alsobe exposed on the product after manufacturing which may cause theproduct to stick to itself, products to stick to one another, or productto stick to the user. Even though ultrasonic bonding has been perceivedto overcome some of the challenges associated with adhesive attachment,opportunities to provide improved ultrasonic bonding patterns stillexist.

Accordingly, there remains a need for ultrasonic bond patterns whichbond components to the chassis of absorbent articles with a greaterresistance to failure. There also remains a need for ultrasonic bondpatterns that bond components to the chassis of absorbent articles withlower variability. Moreover, in some circumstances, there remains a needfor ultrasonic bond patterns that bond stretchable materials in such away so as to maximize the amount of stretch retained in the bond area.

SUMMARY OF THE INVENTION

The present invention relates generally to the use of bond patterns forthe bonding of components to the chassis of an absorbent article. Asdescribed herein in more detail, absorbent articles typically includethree primary components: a bodyside liner, an absorbent core and anouter cover. The chassis of an article typically refers to the areadefined by the bodyside liner and the outer cover. The bodyside linerand the outer cover may run generally contiguous with each other.Typically, the two-dimensional area of the absorbent core is somewhatless than the areas of the bodyside liner and outer cover and theabsorbent core is located between the bodyside liner and the outercover. Many absorbent articles have systems for the fastening of thearticle about a wearer. The fastening systems may include mechanicalfasteners such as a hook material that engages a complementary loopmaterial to join one waist region to the other. It is possible for thehook material to be located directly on the chassis materials of thearticle. More typically however, the hook material is located on a backor front ear portion that is attached to the chassis. The most commonconfiguration is for the hook material to be located on a back earportion for engagement with a complementary loop material located in thefront waist region of the outer cover. Placement of the hook material ona back ear portion that extends laterally outward from the chassisfacilitates joinder of the waist regions around a wearer of the article.

The present invention is directed in part to a disposable absorbentarticle that may include two lateral edges and two longitudinal edges.The absorbent article may also include a front waist region, a backwaist region and a crotch region interconnecting the front waist regionand the back waist region. In addition, the disposable absorbent articleincludes a bodyside liner, an outer cover, and an absorbent core. Thebodyside liner is provided in superimposed relation to the outer coverand the absorbent core is disposed between the outer cover and thebodyside liner. The disposable absorbent article may also include an earportion attached by a plurality of bond elements to one longitudinaledge. The ear portion may be attached in either the front waist regionor the back waist region. The bond elements may form a bond pattern thatdefines a bond pattern area. The bond pattern area may have a PercentStretch of the Bond Pattern Area from about 8% to about 30%. The bondelements may be formed using known techniques such as ultrasonic,adhesive, thermal, laser and pressure. The Percent Stretch of the BondPattern Area is determined by measuring the un-tensioned bond patternwidth; measuring the bond pattern width when loaded to an equivalent of1500 gram/three inches; subtracting the un-tensioned width from theloaded width; dividing by the un-tensioned width; and multiplying thequotient by 100. Alternatively, the bond pattern area may have a PercentStretch of the Bond Pattern Area from about 10% to about 20%.

In another aspect of the present invention, the bond elements may form abond pattern which defines a bond pattern area. The percentage of thebond pattern area that may be bonded may be referred to as the percentbonded area. The percent bonded area may be defined as the area of thebond elements divided by the bond pattern area. The bond pattern areamay be defined by the product of the bond pattern width and the bondpattern length. Preferably, the bond pattern length is the length of thebonded portion that includes a whole number of repeating sequences ofbond pattern elements. For example, if the bond pattern elements arearranged to form a repeating sequence of circle, circle, square, a bondpattern length may include a whole number multiple of this sequence. Thebond pattern length is ideally chosen to be about 75 millimeters, butdesirably corresponds with a multiple of the repeating of the bondelements. The percent bonded area may be between about 5% and about 25%.In another aspect of the present invention, the percent bond area may bebetween about 10% and about 20%. In another aspect, the un-tensionedbond pattern area width may be between about 10 mm and about 18 mm.Alternatively the un-tensioned bond pattern area width may be betweenabout 12 mm and about 16 mm.

In another aspect of the invention the ear may also be attached to thelongitudinal edge of the article with multiple individual adhesiveribbons. The individual adhesive ribbon width may be less than 7 mm. Thebond elements may be formed using known techniques such as ultrasonic,adhesive, thermal, laser and pressure.

In yet another aspect of the present invention, the bond pattern areamay have a Percent Stretch of the Bond Pattern Area from about 8% toabout 30% and the bond pattern may have a bond pattern edge and a BondPattern Integrity value of from 0.30 to 0.60. The Bond Pattern Integrityvalue is defined as the quotient of the fracture line length that isformed by the edges of bond elements and the entire fracture linelength. The fracture line is defined as a path of least resistance thattravels along an edge of the bond pattern. Alternatively, the bondpattern may have a Bond Pattern Integrity value from about 0.35 to about0.55, or from about 0.40 to about 0.55, or from about 0.45 to about0.55.

The bond pattern may also be characterized by the bond element areawhich may impact the path of least resistance and therefore may impactthe Bond Pattern Integrity Value. The bond elements may have a bondelement area of greater than about 0.007585 in². Alternatively, the bondelements may have a bond element area of less than about 0.007585 in².Alternatively, the bond element may have a bond element area of lessthan about 0.00210 in². The bond pattern may also be characterized bythe center-to center spacing between the bond elements. The bond patternmay have a center-to-center spacing along the bond pattern edge ofgreater than about 0.500 inches. Alternatively, the bond pattern canhave a center-to-center spacing along the bond pattern edge of betweenabout 0.500-0.250 inches or a center-to-center spacing along the bondpattern edge of less than about 0.250 inches. The bond element may beformed using known techniques such as adhesive, thermal, laser andpressure. The bond element may have a circular, diamond, or squareshape. Additionally the bond element may have a regular or an irregularshape.

In another aspect, the present invention relates to adisposable-absorbent article that includes two lateral edges, twolongitudinal edges, a front waist region, a back waist region and acrotch region interconnecting the front waist region and back waistregion. In addition, the disposable absorbent article includes abodyside liner, an outer cover, and an absorbent core. The bodysideliner is provided in superimposed relation to the outer cover and theabsorbent core is disposed between the outer cover and the bodysideliner. The disposable absorbent article may also include an ear portionattached by a plurality of bond elements to a longitudinal edge. Thebond elements may form a bond pattern where the bond pattern includestwo or more pairs of longitudinal rows of bond elements. Thelongitudinal rows of bond elements may be offset in the longitudinaldirection by about 30% to about 70% of a longitudinal length of anindividual bond element. There may be three or more, four or more, orfive or more pairs of longitudinal rows of bond elements. Thelongitudinal rows of bond elements may be offset in the longitudinaldirection by about 40% to about 60% of a longitudinal length of anindividual bond element. Alternatively, the longitudinal rows of bondelements may be offset in the longitudinal direction from by about 45%to about 55% of a longitudinal length of an individual bond element.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and are intended toprovide further explanation of the invention claimed. The accompanyingdrawings, that are incorporated in and constitute part of thisspecification, are included to illustrate and provide a furtherunderstanding of the articles of the invention. Together with thedescription, the drawings serve to explain various aspects of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood and furtheradvantages will become apparent when reference is made to the followingdetailed description of the invention and the accompanying drawingswherein like numerals represent like elements. The drawings are merelyrepresentative and are not intended to limit the scope of the appendedclaims.

FIG. 1 representatively shows a perspective view of an example of adisposable absorbent article (an infant diaper) of the presentinvention;

FIG. 2 representatively shows a plan view of the disposable absorbentarticle of FIG. 1 in an unfastened, stretched and laid flat conditionwith the surface of the article which contacts the wearer's skin facingthe viewer and with portions of the article partially cut away to showthe underlying features;

FIG. 3 representatively shows a perspective view of another example of adisposable absorbent article (a diaper pant) of the present invention;

FIG. 4 representatively shows a plan view of the disposable absorbentarticle of FIG. 3 in an unfastened, stretched and laid flat conditionwith the surface of the article which contacts the wearer's skin facingthe viewer and with portions of the article partially cut away to showthe underlying features;

FIG. 5 representatively shows a plan view of an example of an attachmentarea between a back ear portion and the longitudinal side edge of thechassis of a disposable absorbent article including a variegated bondpattern and a uniform bond pattern;

FIG. 6 representatively shows a plan view of a representative example ofa bond pattern, such as may be used to bond ear portions of thedisposable absorbent articles of the invention;

FIGS. 7A, 7B, and 7C representatively show examples of bond patternswith approximately equal-sized round bond elements with superimposedfracture lines along possible paths of least resistance;

FIGS. 8A, 8B, 8C, 8D, 8E, 8F, and 8G representatively show the patternedanvils (at a magnification of 5.3×) used to prepare samples of thepresent invention;

FIGS. 9A and 9B representatively show examples of bond patterns that maybe described as being offset from each other.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure of the invention will be expressed in terms ofits various components, elements, constructions, configurations,arrangements and other features that may also be individually orcollectively be referenced by the term, “aspect(s)” of the invention, orother similar terms. It is contemplated that the various forms of thedisclosed invention may incorporate one or more of its various featuresand aspects, and that such features and aspects may be employed in anydesired, operative combination thereof.

It should also be noted that, when employed in the present disclosure,the terms “comprises”, “comprising” and other derivatives from the rootterm “comprise” are intended to be open-ended terms that specify thepresence of any stated features, elements, integers, steps, orcomponents, and are not intended to preclude the presence or addition ofone or more other features, elements, integers, steps, components, orgroups thereof.

The present invention is directed to solving problems related toabsorbent articles including the durability and integrity with whichcomponents, such as ear portions, are attached to the chassis of thearticles. Additionally, the present invention is directed to improvingthe durability and integrity with which components, such as earportions, are attached to each other. The present invention is alsodirected to maintaining the stretch of the bonded areas used to attachcomponents, such as ear portions to the chassis of the articles. Thisdetailed description of the present invention will include a descriptionof a representative absorbent article including the various componentsof such articles. The description of the representative absorbentarticle will also include a description of the features encompassed bythe present invention.

Representative Absorbent Article

The absorbent articles of the present invention will be described interms of a disposable diaper article and in terms of a diaper pant thatis adapted to be worn by infants about the lower torso. It is understoodthat the features of the present invention are equally adaptable forother types of absorbent articles such as adult incontinence pads, adultincontinence garments, training pants, disposable swim pants andfeminine hygiene pads.

FIG. 1 representatively illustrates an example of a refastenabledisposable diaper, as generally indicated at 20, of the presentinvention. FIG. 2 representatively illustrates the refastenable diaperof FIG. 1 in an unfastened, stretched and laid flat configuration withthe surface of the diaper adapted to contact the wearer's skin facingthe viewer and with portions of the diaper partially cut away to showthe underlying features. FIG. 3 representatively illustrates anotherexample of an absorbent article of the invention, a diaper pantgenerally indicated at 20. FIG. 4 representatively illustrates theprefastened diaper pant of FIG. 3 in an unfastened, stretched and laidflat configuration with the surface of the diaper pant adapted tocontact the wearer's skin facing the viewer and with portions of thediaper pant partially cut away to show the underlying features. Asillustrated in FIG. 2 and FIG. 4, the diaper/diaper pant 20 defines afront waist region 22, a back waist region 24, a crotch region 26 thatextends between and connects the front and back waist regions 22 and 24,a longitudinal direction 38 and a lateral direction 40. The front waistregion 22 includes the portion of the diaper/diaper pant 20 that, whenworn, is positioned on the front of the wearer while the back waistregion 24 includes the portion of the diaper/diaper pant 20 that, whenworn, is positioned on the back of the wearer. The crotch region 26 ofthe diaper/diaper pant 20 includes the portion of the diaper/diaper pant20 that, when worn, is positioned between the legs of the wearer andcovers the lower torso of the wearer.

The diaper/diaper pant 20 defines a pair of laterally opposed side edges30, a pair of longitudinally opposed waist edges 32, an interior surface34 that is configured to contact the wearer, and an exterior surface 36opposite the interior surface 34 that is configured to contact thewearer's clothing in use. The illustrated diaper/diaper pant 20 alsoincludes a substantially liquid impermeable outer cover 42 and a liquidpermeable bodyside liner 44 that can be connected to the outer cover 42in a superposed relation. An absorbent core 28 is located between theouter cover 42 and the bodyside liner 44. The laterally opposed sideedges 30 of the diaper/diaper pant 20 are generally defined by the sideedges of the outer cover 42 that further define leg openings that may becurvilinear. The waist edges 32 of the diaper/diaper pant 20 aregenerally defined by the waist edges of the outer cover 42 and define awaist opening that is configured to encircle the waist of the wearerwhen worm. The absorbent core 28 is configured to contain and/or absorbbody exudates discharged from the wearer. The diaper/diaper pant 20 mayfurther include leg elastics 54, containment flaps 56 and waist elastics58 as are known to those skilled in the art. It should be recognizedthat individual components of the diaper/diaper pant 20 may be optionaldepending upon the intended use of the diaper/diaper pant 20.

The diaper/diaper pant 20 may further include refastenable mechanicalfasteners 60. The mechanical fasteners 60 releasably engage the opposedside edges 30 of the diaper/diaper pant 20 in the opposite waistregions. The mechanical fasteners 60 can include a variety of materialsand surfaces known for mechanical engagement such as buttons, pins,snaps, adhesive tape fasteners, cohesives, mushroom-and-loop fastenersand hook and loop fasteners. Further, the disposable diaper/diaper pant20 may include an attachment panel 66 located on the front or back waistregion 22 and 24, opposite the fasteners 60 to which the fasteners 60can be releasably engaged during use of the diaper/diaper pant 20.

The diaper/diaper pant 20 may be of various suitable shapes. Forexample, in the unfastened configurations as illustrated in FIG. 2 andFIG. 4, the diaper/diaper pant 20 may have an overall rectangular shape,T-shape or an approximately hourglass shape. In the shown embodiments,the diaper/diaper pant 20 has a generally I-shape in an unfastenedconfiguration.

The various components of the diaper/diaper pant 20 are integrallyassembled together employing various types of suitable attachment means,such as adhesive, sonic and thermal bonds or combinations thereof. Inthe shown embodiments, for example, the outer cover 42 and bodysideliner 44 are assembled to each other and to the absorbent core 28 withadhesive, such as a hot melt, pressure-sensitive adhesive. The adhesivemay be applied as a uniform continuous layer of adhesive, a patternedlayer of adhesive, a sprayed pattern of adhesive, or an array ofseparate lines, swirls or dots of adhesive. Alternatively, the absorbentcore 28 may be connected to the outer cover 42 using conventionalfasteners such as buttons, hook and loop type fasteners, adhesive tapefasteners, and the like. The other components of the diaper/diaper pant20 may be suitably connected together using similar means. Similarly,other diaper components, such as the elastic members 54 and 58 and themechanical fasteners 60, may be assembled into the diaper/diaper pant 20article by employing the above-identified attachment mechanisms.Desirably, the majority of the diaper components are assembled togetherusing ultrasonic bonding techniques for reduced manufacturing cost.

The outer cover 42 of the diaper/diaper pant 20, as representativelyillustrated in FIGS. 1 and 3, may suitably be composed of a materialwhich is either liquid permeable or liquid impermeable. It is generallypreferred that the outer cover 42 be formed from a material that issubstantially impermeable to liquids. A typical outer cover 42 can bemanufactured from a thin plastic film or other flexibleliquid-impermeable material. For example, the outer cover 42 may beformed from a polyethylene film having a thickness of from about 0.013millimeter (0.5 mil) to about 0.051 millimeter (2.0 mils). The materialsof the outer cover 42 can be thermally or adhesively laminated together.Suitable laminate adhesives, which can be applied continuously orintermittently as beads, a spray, parallel swirls, or the like, can beobtained from Bostik-Findley, Inc., of Wauwatosa, Wis., U.S.A., or fromNational Starch and Chemical Company, Bridgewater, N.J., U.S.A. If it isdesired to present the outer cover 42 with a more clothlike feeling, theouter cover 42 may be formed from a polyolefin film having a nonwovenweb laminated to the exterior surface thereof, such as a spunbond web ofpolyolefin fibers. For example, a stretch-thinned polypropylene filmhaving a thickness of about 0.015 millimeter (0.6 mil) may be thermallylaminated thereto a spunbond web of polypropylene fibers. Thepolypropylene fibers may have a fiber diameter of about 15 to 20microns, which nonwoven web has a basis weight of about 17 grams persquare meter (0.5 ounce per square yard). The outer cover 42 may includebicomponent fibers such as polyethylene/polypropylene bicomponentfibers. Methods of forming such clothlike outer covers are known tothose skilled in the art. The outer cover 42 may also be an extensibleouter cover such as the outer covers described in U.S. Pat. No.6,552,245 issued on Apr. 22, 2003 to Roessler et al. The outer cover 42may also be a biaxially stretchable outer cover such as the outer coversdescribed in U.S. patent application Ser. No. 09/698,517 filed on Oct.27, 2000 by Vukos et al.

The outer cover 42 may be formed of a woven or nonwoven fibrous weblayer which has been totally or partially constructed or treated toimpart a desired level of liquid impermeability to selected regions thatare adjacent or proximate the absorbent core 28. Still further, theouter cover 42 may optionally be composed of a micro-porous “breathable”material which permits vapors to escape from the absorbent core 28 whilestill preventing liquid exudates from passing through the outer cover42. For example, the outer cover 42 may include a vapor permeablenon-woven facing layer laminated to a micro-porous film. Suitable“breathable” outer cover materials are described in U.S. Pat. No.5,695,868 issued Dec. 9, 1997 to McCormack et al. and U.S. Pat. No.5,843,056 issued Dec. 1, 1998 to Good et al., the descriptions of whichare hereby incorporated by reference. Still further, the outer cover 42may also be an elastomeric material such as a stretch-thermal laminate(STL), neck-bonded laminate (NBL), or stretch-bonded laminate (SBL)material. Methods of making such materials are well known to thoseskilled in the art and are described in U.S. Pat. No. 4,663,220 issuedMay 5, 1987 to Wisneski et al., U.S. Pat. No. 5,226,992 issued Jul. 13,1993 to Morman, and European Patent Application No. EP 0 217 032published on Apr. 8, 1987 in the names of Taylor et al., the disclosuresof which are hereby incorporated by reference. The outer cover 42 canalso be embossed or otherwise provided with a matte finish to provide amore aesthetically pleasing appearance.

In order to reduce the perception that the outer cover 42 feels damp orclammy, the diapers/diaper pants 20 of the invention may include aspacer or ventilation layer (not shown in Figures) between thegarment-facing surface of the absorbent core 28 and the outer cover 42.The ventilation layer may include one or more nonwoven materials, forexample a spunbond-meltblown-spunbond nonwoven material.

The representative absorbent articles of the invention include abodyside liner 44 in superimposed relation to the outer cover 42. Thebodyside liner 44, as representatively illustrated in FIG. 2 and FIG. 4,suitably presents a bodyfacing surface that is compliant, soft feeling,and nonirritating to the wearer's skin. Further, the bodyside liner 44may be less hydrophilic than the absorbent core 28, to present arelatively dry surface to the wearer, and may be sufficiently porous tobe liquid permeable, permitting liquid to readily penetrate through itsthickness. A suitable bodyside liner 44 may be manufactured from a wideselection of web materials, such as porous foams, reticulated foams,apertured plastic films, natural fibers (for example, wood or cottonfibers), synthetic fibers (for example, polyester or polypropylenefibers), or a combination of natural and synthetic fibers. The bodysideliner 44 is suitably employed to help isolate the wearer's skin fromliquids held in the absorbent 28. The bodyside liner 44 can also be madefrom extensible materials as are described in U.S. Pat. No. 6,552,245issued on Apr. 22, 2003 to Roessler et al. The bodyside liner 44 canalso be made from biaxially stretchable materials as are described inU.S. patent application Ser. No. 09/698,517 filed on Oct. 27, 2000 byVukos et al.

Various woven and nonwoven fabrics can be used for the bodyside liner44. For example, the bodyside liner may be composed of a meltblown orspunbond web of polyolefin fibers. The bodyside liner 44 may also be abonded-carded web composed of natural and/or synthetic fibers. Thebodyside liner 44 may be composed of a substantially hydrophobicmaterial, and the hydrophobic material may optionally be treated with asurfactant or otherwise processed to impart a desired level ofwettability and hydrophilicity. In a particular embodiment of thepresent invention, the bodyside liner 44 is made from a nonwoven,spunbond, polypropylene fabric composed of fibers having a fiberdiameter of about 21 to 23 microns formed into a web having a basisweight of about 20 grams per square meter and a density of about 0.13grams per cubic centimeter. The fabric may be surface treated with about0.3 weight percent of a surfactant, such as a surfactant commerciallyavailable from Hodgson Textile Chemicals, Inc. under the tradedesignation AHCOVEL Base N-62. The surfactant may be applied by anyconventional means, such as spraying, printing, brush coating or similartechniques. The surfactant may be applied to the entire bodyside liner44 or may be selectively applied to particular sections of the bodysideliner 44, such as the medial section along the longitudinal centerlineof the diaper, to provide greater wettability of such sections. Thebodyside liner 44 may further include a lotion or treatment appliedthereto that is configured to be transferred to the wearer's skin.Suitable compositions for application to the bodyside liner 44 aredescribed in U.S. Pat. No. 6,149,934 that issued to Krzysik et al. onNov. 21, 2000.

The representative absorbent articles of the invention can include anabsorbent core 28 disposed between the outer cover 42 and the bodysideliner 44. The absorbent core 28 of the diaper/diaper pant 20, asrepresentatively illustrated in FIG. 1 and FIG. 3, may suitably includea matrix of hydrophilic fibers, such as a web of cellulosic fluff, mixedwith particles of a high-absorbency material commonly known assuperabsorbent material. In a particular aspect, the absorbent core 28includes a matrix of cellulosic fluff, such as wood pulp fluff, andsuperabsorbent hydrogel-forming particles. The wood pulp fluff may beexchanged with synthetic, polymeric, meltblown fibers or with acombination of meltblown fibers and natural fibers. The superabsorbentparticles may be substantially homogeneously mixed with the hydrophilicfibers or may be nonuniformly mixed. Alternatively, the absorbent core28 may include a laminate of fibrous webs and superabsorbent material orother suitable matrix for maintaining a superabsorbent material in alocalized area.

The absorbent core 28 may have any of a number of shapes. For example,the absorbent core 28 may be rectangular, I-shaped, or T-shaped. It isgenerally preferred that the absorbent core 28 is narrower in theintermediate section than in the front or rear waist sections of thediaper 20. The absorbent core 28 may be provided by a single layer or,in the alternative, may be provided by multiple layers, all of whichneed not extend the entire length and width of the absorbent core 28. Ina particular aspect of the invention, the absorbent core 28 can begenerally T-shaped with the laterally extending cross-bar of the “T”generally corresponding to the front waist region 22 of the absorbentarticle for improved performance, especially for male infants.

The size and the absorbent capacity of absorbent core 28 should becompatible with the size of the intended wearer and the liquid loadingimparted by the intended use of the absorbent article. Further, the sizeand the absorbent capacity of the absorbent core 28 can be varied toaccommodate wearers ranging from infants through adults. In addition, ithas been found that with the present invention, the densities and/orbasis weights of the absorbent core 28 can be varied.

The high-absorbency material may be selected from natural, synthetic,and modified natural polymers and materials. The high-absorbencymaterials may be inorganic materials, such as silica gels, or organiccompounds, such as crosslinked polymers. The term “crosslinked” refersto methods for effectively rendering normally water-soluble materialssubstantially water insoluble but swellable. Such methods include, forexample, physical entanglement, crystalline domains, covalent bonds,ionic complexes and associations, hydrophilic associations such ashydrogen bonding, and hydrophobic associations or Van der Waals forces.

Examples of synthetic, polymeric, high-absorbency materials include thealkali metal and ammonium salts of poly(acrylic acid) andpoly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleicanhydride copolymers with vinyl ethers and alpha-olefins, poly(vinylpyrrolidone), poly(vinyl morpholinone), poly(vinyl alcohol), andmixtures and copolymers thereof. Further polymers suitable for use inthe absorbent core 28 include natural and modified natural polymers,such as hydrolyzed acrylonitrile-grafted starch, acrylic acid graftedstarch, methyl cellulose, carboxymethyl cellulose, hydroxypropylcellulose, and the natural gums, such as alginates, xanthan gum, locustbean gum, and the like. Mixtures of natural and wholly or partiallysynthetic absorbent polymers can also be useful in the presentinvention.

The high absorbency material may be in any of a wide variety ofgeometric forms. As a general rule, it is preferred that the highabsorbency material be in the form of discrete particles. However, thehigh absorbency material may also be in the form of fibers, flakes,rods, spheres, needles, or the like. In general, the high absorbencymaterial is present in the absorbent core 28 in an amount of from about5 to about 90 percent by weight, desirably in an amount of at leastabout 30 percent by weight, and even more desirably in an amount of atleast about 50 percent by weight based on a total weight of theabsorbent core 28. For example, in a particular aspect, the absorbentcore 28 may include a laminate which includes at least about 50 percentby weight and desirably at least about 70 percent by weight ofhigh-absorbency material overwrapped by a fibrous web or other suitablematerial for maintaining the high-absorbency material in a localizedarea.

An example of high-absorbency material suitable for use in the presentinvention is DRYTECH 2035 polymer available from Dow Chemical, abusiness having offices in Midland, Mich. Other suitable superabsorbentsmay include FAVOR SXM 880 polymer obtained from Stockhausen, a businesshaving offices in Greensboro, N.C.

Optionally, a substantially hydrophilic tissue or nonwoven wrapsheet(not illustrated) may be employed to help maintain the integrity of thestructure of the absorbent core 28. The wrapsheet is typically placedabout the absorbent core 28 over at least the two major facing surfacesthereof. The wrapsheet may be composed of an absorbent cellulosicmaterial, such as creped wadding or a high wet-strength tissue. In oneaspect of the invention, the wrapsheet may be configured to provide awicking layer that helps to rapidly distribute liquid over the mass ofabsorbent fibers constituting the absorbent core 28.

Due to the thinness of absorbent core 28 and the high absorbencymaterial within the absorbent core 28, the liquid uptake rates of theabsorbent core 28, by itself, may be too low, or may not be adequatelysustained over multiple insults of liquid into the absorbent core 28. Toimprove the overall liquid uptake and air exchange, the diaper/diaperpant 20 of the different aspects of the present invention may furtherinclude a porous, liquid-permeable layer of surge management material53, as representatively illustrated in FIG. 2 and FIG. 4. The surgemanagement layer 53 is typically less hydrophilic than the absorbentcore 28, and has an operable level of density and basis weight toquickly collect and temporarily hold liquid surges, to transport theliquid from its initial entrance point and to substantially completelyrelease the liquid to other parts of the absorbent core 28. Thisconfiguration can help prevent the liquid from pooling and collecting onthe portion of the diaper/diaper pant 20 positioned against the wearer'sskin, thereby reducing the feeling of wetness by the wearer. Thestructure of the surge management layer 53 also generally enhances theair exchange within the diaper/diaper pant 20.

Various woven and nonwoven fabrics can be used to construct the surgemanagement layer 53. For example, the surge management layer 53 may be alayer composed of a meltblown or spunbond web of synthetic fibers, suchas polyolefin fibers. The surge management layer 53 may also be abonded-carded-web or an airlaid web composed of natural and syntheticfibers. The bonded-carded-web may, for example, be a thermally bondedweb that is bonded using low melt binder fibers, powder or adhesive. Thewebs can optionally include a mixture of different fibers. The surgemanagement layer 53 may be composed of a substantially hydrophobicmaterial, and the hydrophobic material may optionally be treated with asurfactant or otherwise processed to impart a desired level ofwettability and hydrophilicity. In a particular aspect, the surgemanagement layer 53 includes a hydrophobic, nonwoven material having abasis weight of from about 30 to about 120 grams per square meter.

The absorbent articles of the invention can include additionalcomponents. For example, as representatively illustrated in FIGS. 14,the disposable diaper/diaper pant 20 may include a pair of containmentflaps 56 that are configured to provide a barrier to the lateral flow ofbody exudates. The containment flaps 56 may be located along thelaterally opposed side edges 30 of the diaper/diaper pant adjacent theside edges of the absorbent core 28. Each containment flap 56 typicallydefines an unattached edge that is configured to maintain an upright,perpendicular configuration in at least the crotch region 26 of thediaper/diaper pant 20 to form a seal against the wearer's body. Thecontainment flaps 56 may extend longitudinally along the entire lengthof the absorbent core 28 or may only extend partially along the lengthof the absorbent core 28. When the containment flaps 56 are shorter inlength than the absorbent core 28, the containment flaps 56 can beselectively positioned anywhere along the side edges 30 of diaper/diaperpant 20 in the crotch region 26. In a particular aspect of theinvention, the containment flaps 56 extend along the entire length ofthe absorbent core 28 to better contain the body exudates. Suchcontainment flaps 56 are generally well known to those skilled in theart.

The diaper/diaper pant 20 of the different configurations of the presentinvention may further include elastics at the waist edges 32 and sideedges 30 of the diaper/diaper pant 20 to further prevent leakage of bodyexudates and support the absorbent core 28. For example, asrepresentatively illustrated in FIGS. 1-4, the diaper/diaper pant 20 ofthe present invention may include a pair of leg elastic members 54 thatare connected to the laterally opposed side edges 30 of thediaper/diaper pant 20 in the crotch region 26. The diaper/diaper pant 20may also include a pair of waist elastic members 58 that is connected tothe longitudinally opposed waist edges 32 of the diaper/diaper pant 20.The leg elastics 54 and waist elastics 58 are generally adapted to fitabout the legs and waist of a wearer in use to maintain a positive,contacting relationship with the wearer to effectively reduce oreliminate the leakage of body exudates from the diaper/diaper pant 20.

Materials suitable for use as the leg elastics 54 and waist elastics 58are well known to those skilled in the art. Exemplary of such materialsare sheets or strands or ribbons of a polymeric, elastomeric materialthat may be adhered to the outer cover 42 in a stretched position, orthat may be attached to the outer cover 42 while the outer cover ispleated, such that elastic constrictive forces are imparted to the outercover 42. The leg elastics 54 may also include such materials aspolyurethane, synthetic and natural rubber. The waist elastics 58 may beformed by elastic strands attached to the outer cover 42 or they may beformed by attaching separate pieces of stretchable materials to thewaist regions of the article. For example, the waist elastics 58 mayinclude a piece of stretch-bonded laminate material attached to theinterior surface 34 of the article to form a waistband. Elasticity maybe added or incorporated into the waist opening of absorbent articlesutilizing a variety of known approaches.

The absorbent articles of the invention may include one or morecomponents that extend laterally outward from the longitudinal sides ofthe article. Typically, the longitudinal sides are defined by thematerials forming the chassis of the diaper/diaper pant 20. The chassismay be defined by the outer cover 42 and bodyside liner 44 materials.Components that extend laterally outward may include front ear portions64 and back ear portions 62. The front ear portions 64 and the back earportions 62 may be formed of one or more materials and may includelaminates of materials. The front ear portions 64 and the back earportions 62 improve the fit of the absorbent article. More specifically,the front ear portions 64 may provide additional coverage around thewaist of the wearer and they may assist caregivers with positioning thefront waist region 22 on the wearer of the article. The front earportions 64 may also include mechanical fastening materials such thatthe front ear portions 64 contribute to the overall fastening system ofthe article. The back ear portions 62 may also provide coverage aroundthe waist of the wearer. More specifically, the back ear portions 62 mayprovide the bridging material between the back waist region 24 of thearticle and the front waist region 22 such that the back ear portions 62form part of the article's waist opening and an upper edge of thearticle's leg openings. Additionally, the back ear portions 62 mayinclude fastening materials that facilitate joining of the back waistregion 24 with the front waist region 22. For example, the back earportions 62 may include fasteners 60 selected for engagement with anattachment panel 66 in the front waist region 22 of the article.

Presently available infant diapers typically include back ear portions62 that include a stretchable material. When the back ear portions 62include a stretchable material, the back ear portions 62 may increasethe range with which the fasteners 60 may be engaged into the attachmentpanel 66 or directly into the outer cover 42. Further, when the back earportions 62 include a stretchable material, the article may be worn by agreater range of users as a result of the increased fit range. Anexemplary material from which the back ear portions 62 may beconstructed is a necked bonded laminate material having two nonwoven(e.g. spunbond) facings with an elastomeric film (e.g. KRATON film)laminated in between. Other suitable stretchable materials are known inthe art. Depending on the design of the article, it may also bedesirable for the front ear portions 64 to include a stretchablematerial.

When the product form of the absorbent article is a training pant or aswim pant, the back ear portions 62 and the front ear portions 64 areunderstood to include the side panels that are attached to thelongitudinal sides 30 of the article and also are attached to each otherto form side seams of the article. Typically, the side panels oftraining pants and swim pants are made from stretchable materials. Theside panels' ability to stretch allows these products to be pulled onthe wearer like underpants.

The diaper pant 20 form of the present invention (representativelyillustrated in FIG. 3 and FIG. 4) may be described as a hybrid betweenan infant diaper that is typically removed and applied while the childis lying down and a training pant that is put on like underpants. Theproduct form may be referred to as a diaper pant because the diaper pantmay be applied and removed as either a diaper or a pant. A diaper pantmay have a back ear portion 62 and a front ear portion 64 where the backear portion 62 and front ear portion 64 are attached to each other by apassive side bond 74. The passive side bond 74 may be selected to bereadily tearable by caregivers during the process of “converting” thediaper pant from a pant to a diaper. Desirably, the passive side bond 74is easily opened/broken without tearing of the materials used to formthe back ear portion 62 and the front ear portion 64.

With each of the product forms, the back ear portions 62 and the frontear portions 64 may be attached to the longitudinal side edges 30 of thearticle by bonding techniques, such as ultrasonic bonding. Use ofultrasonic bonding techniques tends to form discrete bond points. Thebond patterns of the invention, as will be discussed herein, may beformed using known techniques such as adhesive, thermal, laser andpressure that are capable of forming the patterns. Ultrasonic bondingwill be referred to for purposes of example. With articles of theinvention, the back ear portions 62 and the front ear portions 64 may beattached to one or more of the chassis materials using one or more bondpatterns. The articles of the invention may include an attachment area76 where the attachment area 76 includes an overlapping area of thematerial forming the outer cover 42 and the material forming either aback ear portion 62 or a front ear portion 64. The attachment area 76may further include a variegated bond pattern 70 and a uniform bondpattern 72 where each bond pattern provides attachment between the outercover 42 material and the ear portion material. The attachment area 76may also include an overlapping area of the material forming thebodyside liner 44 and the material forming either a back ear portion 62or a front ear portion 64. Additionally, the attachment area 76 mayinclude an overlapping area of the material forming the outer cover 42,the material forming the bodyside liner 44 and the material formingeither a back ear portion 62 or a front ear portion 64.

The variegated bond pattern 70 may be formed by a plurality of bondpoints that are variable in location with respect to each other. Putdifferently, the bond points of the variegated bond pattern 70 may notall be located equidistantly from each other. While the bond points ofthe variegated bond pattern 70 may spaced irregularly with respect toeach other, the variegated bond pattern 70 may have a repeating patternappearance. The uniform bond pattern 72 may be formed by a plurality ofbond points that are regular in location with respect to each other. Putdifferently, the bond points of the uniform bond pattern 72 are locatedgenerally equidistantly from each other. The variegated bond pattern 70and the uniform bond pattern 72 may be immediately adjacent to eachother as illustrated in FIG. 5 or the patterns may have some open spacein between them. The bond patterns may be formed by ultrasonic bonds orby other bonding techniques capable of providing individual bond points.

FIG. 6 illustrates a representative example of a bond pattern 81 thatmay be selected for attaching a back ear portion 62 to the chassis of adiaper 20. In addition to ear portions 62/64 being attached to thechassis through the use of variegated bond pattern 70 and uniform bondpatterns 72, bond patterns may be selected to provide increased bondstrength and tear resistance.

A bond pattern may be understood to include a plurality of bond elementslocated in general proximity to each other (such as the array of bondelement s shown in FIG. 6). The bond pattern may be defined by itsdimensions. For example, a bond pattern 81 width “W” may be defined bythe distance in the lateral direction 40 between the first edge 80 ofthe bond pattern, and the second edge 82 of the bond pattern. A bondpattern width can be measured at any point along the length of the bondpattern. The bond pattern edge may be curvy which may result in the bondpattern width varying along the length of the bond pattern. When a bondpattern has curvy edge, the bond pattern width may be defined as theaverage bond pattern width. The bond pattern edge may be curvy whenthree or more consecutive bond elements are located away from a straightbond pattern edge.

A bond element area is defined for non-hollow bond elements 85 as thegeometric area of the bond element 85. For hollow bond elements, such asa bond element in the shape of a “donut”, the bond element area isdefined as the area enclosed by the outer circumference of the bondelement. For a “donut” shaped bond element this area would include thearea of the “donut hole.” All bond elements 85 shown in all figures arenon-hollow.

If a bond pattern 81 securing an ear portion 62 to an absorbent article(FIG. 7A) is susceptible to failure, the failure is likely to occuralong a path of least resistance. The path of least resistance maycorrespond to portions of bond elements' circumferences. The path ofleast resistance may also contain portions corresponding to spacesbetween bond elements 86. This path of least resistance may propagatealong either edge 80, 82 of the bond pattern 81.

FIG. 7A representatively illustrates an example of a bond pattern 81with approximately equal sized round, non-hollow bond elements 85superimposed with a possible fracture line 83 following a path of leastresistance along a first edge 80 of the bond pattern. The fracture line83 may extend the entire length of the first edge 80 of the bondpattern, however only the fracture line 83 between five bond elements 85is shown in FIG. 7A. The fracture line 83 begins at a location where thecircumference of a first bond element 84 contacts the first edge 80 ofthe bond pattern. The fracture line 83 may follow the circumference ofthe first bond element 84 away from the first edge 80 of the bondpattern until the fracture line 83 is perpendicular to the shortest line86 connecting the first bond element 84 and a second bond element 88.The fracture line 83 may then follow this shortest line 86 until thefracture line 83 intersects with the circumference of the second bondelement 88. The fracture line then follows the circumference of thesecond bond element 88 towards the intersection of the circumference ofthe second bond element 88 with the first edge 80 of the bond pattern.The fracture line 83 may continue in this manner along the first edge 80of the bond pattern. Hence, the fracture line 83 may contain portionsformed by the circumferences of bond elements as well as portions formedby the straight lines between bond elements 84, 88. The relationship ofthe portions formed by the circumferences of bond elements 84, 88 and ofthe portions formed by the straight lines 86 between bond elements 84,88 is described in detail below.

FIG. 7B representatively illustrates a second example of a bond patternwith approximately equal sized round, non-hollow bond elementssuperimposed with a possible fracture line 83 following a path of leastresistance along a first edge 80 of the bond pattern. As with theexample shown in FIG. 7A, the fracture line 83 may extend the entirelength of the first edge 80 of the bond pattern, however, only a portionthe fracture line 83 between five bond elements is shown in FIG. 7B. Inaddition, a blow up of the five bond elements from FIG. 7B is shown inFIG. 7C. In this example, as above, the fracture line 83 may start wherethe edge of a first bond element 90 contacts the first edge 80 of thebond pattern. The fracture line 83 may then follow the circumference ofthe bond element 90 away from the contact with the first edge 80 of thebond pattern until the fracture line 83 contacts the shortest segment 96connecting the first bond element 90 and a second bond element 92 thatis not located on the first edge 80 of the bond pattern. The fractureline 83 may then follow this first shortest segment 96 until thefracture line 83 intersects with the circumference of the second bondelement 92. The fracture line 83 may then follow the circumference ofthe second bond element 92 starting in the direction of the first edge80 of the bond pattern and continuing until the fracture line 83contacts the shortest segment 98 connecting the second bond element 92and a third bond element 94 located on the first edge 80 of the bondpattern. The fracture line 83 may then follow this shortest segment 98until the fracture line 83 intersects with the circumference of thethird bond element 94. The fracture line 83 may then follow thecircumference of the third bond element 94 towards the intersection ofthe third bond element 94 with the first edge 80 of the bond pattern.The fracture line 83 may then repeat this pattern.

This fracture line 83 may travel from the first bond element 90 locatedon the first edge 80 of the bond pattern to the second bond element 92not located on the first edge 80 of the bond pattern if this is the pathof least resistance. The fracture line 83 in FIG. 7B will be the path ofleast resistance if the sum of the length of the shortest segment 96between the first bond element 90 and the second bond element 92 and thelength of the shortest segment 98 between the second bond element 92 andthe third bond element 94 is less then the length of the shortestsegment 93 between the first bond element 90 and the third bond element94. If the sum of the length of segment 96 and the length of segment 98is equal to or greater than the length of segment 93, the fracture line83 will likely not travel to a bond element not located on the firstedge 80 of the bond pattern; instead, the fracture line will travel inthe manner shown in FIG. 7A.

Desirably, the bond patterns of the invention balance the contributionsto the integrity of the bonded composite by design of the bond pattern.More specifically the invention balances contributions from bondelements and contributions from the spaces between bond elements. Withrespect to the fracture line 83, it is desirable to balance the portionof the fracture line 83 that may travel along the circumference of bondelements with the portion of the fracture line 83 that may travelbetween bond elements (traveling through unbonded material). Morespecifically, when the length of the fracture line that travels alongthe circumference of bond elements is equal to the length of thefracture line that travels between bond elements, a maximum bondstrength may be attained. The maximum bond strength occurs when a BondPattern Integrity Value is equal to 0.500.

The Bond Pattern Integrity Value is defined as the quotient of thefracture line length that is formed by the edges of bond elements andthe entire fracture line length. For example, for circular bond elementshaving diameter “D” (see FIG. 7A) and a fracture line 83 that travelsbetween bond elements located on the edge of the bond width, withcenter-to-center spacing “S” (see FIG. 7A), the calculation for the BondPattern Integrity Value is: [((Π*D)/2)/(((Π*D)/2)+S−D)].

In a second example, the bond elements 85 may be square-shaped and havea side length “L”. For square shaped bond elements 85, the fracture linemay travel between bond elements 85 located on the edge of the bondpattern, with a side parallel to the edge of the bond pattern, and withcenter-to-center spacing “S”, the calculation for the Bond PatternIntegrity Value is: [L/S].

In a third example, the bond elements 85 may be square-shaped and have aside length “L”. For square shaped bond elements 85, the fracture linemay travel between bond elements 85 located on the edge of the bondpattern, with a side 45 degrees to the edge of the bond pattern (diamondorientation), and with center-to-center spacing “S”, the calculation forthe Bond Pattern Integrity Value is: [(2*L)/((2*L)+S−(L* √2))].

These exemplary calculations are representative of how the Bond PatternIntegrity Value may be calculated for bond patterns of the invention.For more complex geometries, measurement using optical methods known inthe art may be used to determine the Bond Pattern Integrity Value.

The Bond Pattern Integrity Values and the strength of the bonds of bondpatterns 81 representing bond patterns of the invention were determined.In addition, the Bond Pattern Integrity Values of presently availablecommercial bond patterns were measured. For example PAMPERS NOCTURNAdiapers (available from the Procter & Gamble Co.) purchased in Brazil,in June 2003, and PAMPERS Premium diapers (available from the Procter &Gamble Co.) purchased in the United States, in June 2003 were tested.These commercially available diapers included back ear portions that arebonded to the longitudinal edge of the chassis of diapers.

The Bond Pattern Integrity Value was determined by first measuringrequired lengths, radii, and angles of the bond elements of the bondpattern from bonded materials. A SWIFT microscope model # 3208 was usedto make the measurements of the bond patterns. The measurements weremade at 4× magnification. The ocular used was a SWIFT POINTMASTER ocularEW 10×D/20.50 14.5 MM, which is a scaled ocular that was calibrated to agraduated slide with a 2 mm measurement divided into units of 0.01 mm.The slide was manufacture by American Optical of Southbridge, Mass. Thiscalibration indicated that 67 gradations equaled 2 mm. Pictures may betaken for irregular shaped bonds and image analysis may be used tocalculate the dimensions needed when the picture contains a referencesuch as some measurement device in the picture. A person skilled in theart will recognize many equivalent methods possible of attaining similarresults.

From these measurements, the Bond Pattern Integrity Value may becalculated, either with one of the above formulas, an appropriateformula for the geometry of the bond elements and bond pattern, or aphysical measurement of the portions of the fracture line. The BondPattern Integrity Values calculated for the PAMPERS diapers products areprovided in Table 3. below. In addition to measuring aspects of the bondpatterns used on PAMPERS diapers, the bond element diameter “D” forcircular bond elements or side length “L” for square bond elements, andcenter-to center spacing “S” for bond patterns of the invention weredetermined and are provided in Table 1. below.

All examples of bond patterns of the invention were prepared by placing4.3 osy NBL between spunbond reversibly neck-stretched liner materialand a poly spunbond outer cover material, such as that used on HUGGIESSupreme diapers and ultrasonically bonding with a plunge bonder having aflat horn and a patterned anvil. The neck-bonded laminate material isrepresentatively of a suitable material that may be used to form an earportion 62.

The patterned anvils used to make the samples of the invention weremagnified 5.3 times and photographed. These photographs are shown inFIGS. 8A to 8G. The patterned anvil of Code A is shown in FIG. 8A. Thepatterned anvil of Code B is shown in FIG. 8B. The patterned anvil ofCode C is shown in FIG. 8C. The patterned anvil of Code D is shown inFIG. 8D. The patterned anvil of Code E is shown in FIG. 8E. Thepatterned anvil of Code F is shown in FIG. 8F. The patterned anvil ofCode G is shown in FIG. 8G. TABLE 1 Center-to-Center Diameter (Round)Spacing Along Edge Bond Element Length of Side of the Bond Code Geometry(Square) (mm) Pattern (mm) A Round 1.641 3.125 B Square 1.104 5.912(Diamond Orientation) C Square 1.104 4.167 D Round 0.746 5.594 E Round0.746 3.972 F Round 1.194 3.158 G Round 0.985 2.350

In addition to measuring the parameters relevant to calculate the BondPattern Integrity Value, the bond patterns of the invention may also becharacterized by the strength of the bonds. In order to test thestrength of the bond between the materials bonded with the bond patternsof the invention, Codes A-G were tested according to ASTM test procedureD-5733-99 modified in two ways, from which a stress-strain curve wascalculated. The first modification of ASTM D-5733-99 is the eliminationof the initiating cut. The second modification of ASTM D-5733-99 is theplacement of the jaws to be parallel with the edges of the bond patternone inch from the edge of the bond pattern. The data recorded in Table2. below indicates the Bond Energy of the bond patterns. The Bond Energyis the amount of energy required to completely rupture the bonds, whichis represented by the area under the stress-strain curve. The strengthof the bonds is a function of many factors. Some of these factors arethe chemical composition of the material being bonded, material weight,horn amplitude and Bond Pattern Integrity Value. For this reason,comparison of the strength of the bond for samples made with non-uniformmaterials may not be useful. For Codes A-G, the same material andmaterial basis weights were used. Additionally, the same bonder wasused. The Bond Pattern Integrity Values for PAMPERS Noturna, PAMPERSPremium diapers, and HUGGIES Supreme diapers (available from theKimberly-Clark Corp) were determined and are recorded in Table 3. below.TABLE 2 Bond Pattern Integrity Value Bond Energy Code (Calculated Basedon Values in Table 1.) (grams*cm) A 0.635 16392 B 0.337 17779 C 0.26513497 D 0.195 5959 E 0.267 4655 F 0.488 20483 G 0.531 12978

TABLE 3 Code Bond Pattern Integrity Value PAMPERS Noturna diapers 0.679PAMPERS Premium diapers 0.830 HUGGIES Supreme diapers 0.608

The Bond Pattern Integrity Value approaches a minimum of zero when thecircumference of the bond elements 85 get small and the center-to-centerspacing gets large. Consequently, there are very few bond elements 85along the fracture line 83 to bond the material together. Additionally,the Bond Pattern Integrity Value approaches a maximum of one when thecircumference of the bond elements 83 gets large and thecenter-to-center spacing gets small. When this occurs, the fracture line83 exists entirely on the circumference of bond elements 85. Addedstrength is achieved when the fracture line 83 makes the transition froma bond element circumference to the material in between bond elements85. Up to a point the more transitions per length of bonded materialwill increase the strength of the bond. Additionally, an optimum BondPattern Integrity Value exists for a given bond set-up of a givenmaterial and a given bonding technique. For a given bond pattern set-up,as the Bond Pattern Integrity Value increases from zero, there is morebonding holding the materials together and the strength of the bondpattern increases. For the same bond pattern set-up, as the Bond PatternIntegrity Value approaches one, there is less and less material betweenbonds to provide strength and the strength of the bond decreases. TheBond Pattern Integrity Value for bond pattern of the invention may rangefrom about 0 to 1, more specifically from about 0.2 to 0.8, and morespecifically from about 0.3 to 0.7.

In addition to the Bond Pattern Integrity Value, another aspect relatingto the orientation and the spacing of the bond elements 85 of bondpatterns is the percent bonded area.

The percent bonded area may be defined as the area of bond elementsdivided by the bond pattern area. The bond pattern area may be definedby the product of the bond pattern width and the bond pattern length.The bond pattern width is described previously herein. The bond patternlength may be the entire length of the bond pattern that is on theabsorbent article. Preferably, the bond pattern length is the length ofthe bonded portion that includes a whole number of repeating sequencesof bond pattern elements. For example, if the bond pattern elements arearranged to form a repeating sequence of circle, circle, square, a bondpattern length would include a whole number multiple of this sequence.To determine the area of bond elements of a bond pattern with only onetype of bond element, the dimensions of the bond element are determinedusing the method described above, and the area of the bond element ismultiplied by the number of bond elements in the bond pattern area. Thebond pattern length is ideally chosen to be about 75 millimeters, butdesirably corresponds with a multiple of the repeating of the bondelements.

Desirably, absorbent articles are formed from extensible and stretchablematerials so as to improve the fit of the articles. A stretchablematerial (such as may be used to form an ear portion 62/64 is a materialthat is capable of extending upon application of a tensile force andcapable of retracting either partially or close to completely to itsoriginal dimension(s) upon removal of the force depending on the desireduse within the absorbent article. An extensible material is a materialthat is capable of extending upon application of a tensile force, butthe extension is permanent. Stretchable and extensible materials may bemore expensive than non-stretchable and non-extensible materials.Desirably, the inclusion of stretch or extensibility to absorbentarticles using these materials may be optimized by minimizing thereduction in stretch or extensibility that may be caused by bonding. Ameasure of the amount of stretch or extensibility remaining in thecomponents after bonding is the percent stretch of the bond patternarea.

The percent stretch of a bond pattern area may be determined by firstmarking the edges of the bond pattern of a bonded area of materials froman absorbent article. The bonded area of materials is then cut into athree inch by approximately six inch rectangle. The rectangle is cut insuch a way that the bond length on the rectangle is three inches and thebond pattern area is approximately centered in the six inch dimension. Afirst three inch clamp is applied to one edge of the rectangle, suchthat the clamp is attached parallel to the edge of the bond pattern,approximately one inch away from the first edge of the bond pattern. Thefirst three inch clamp is then attached to a hanger which allows therectangle to hang from the first three inch clamp. The distance betweenthe marks is measured indicating the un-stretched bond pattern width. Asecond three inch clamp that has been weighted to a total of 1500 gramsis then attached parallel to the second edge of the bond patternopposite the first three inch clamp, approximately one inch away fromthe second edge of the bond pattern. The clamps are now aligned awayfrom the bond pattern allowing room to measure between the marks. Afterthe weight has been allowed to hang for 10 seconds, the distance betweenthe marks is measured indicating the stretched bond pattern width. Bysubtracting the un-stretched bond pattern width from the stretched bondpattern width, then dividing by the un-stretched bond pattern width andmultiplying the quotient by 100, the percent stretch of the bond patternarea may be determined. If the bonded area of material has a bond lessthan three inches in length, the width and weight of the second clamsmay be adjusted to deliver an equivalent loading 1500 gram/three inches.

The percent bonded area, bond energy, and percent stretch of the bondpattern area of Codes A-G were determined via the methods describedabove and are provided in Table 4. below. TABLE 4 Percent Stretch ofPercent Bonded Area Bond Energy the Bond Pattern Area Code (%)(grams*cm) (%) A 15.9 16392 10.5 B 6 17779 25.7 C 6.2 13497 20.0 D 4.85959 17.5 E 4.6 4655 23.2 F 20.2 20483 5.0 G 15.7 12978 8.3

For a given bond pattern set-up, as the percent bond area increases,there is more area to contribute to the integrity of the bond patternand the bond energy generally increases. For the same bond patternset-up, as the percent bond area increases, there is less free materialto allow the bond area to stretch and the percent stretch of the bondpattern area generally decreases. The percent bond area may range from 0to 100, more specifically form 1 to 50, more specifically from 2 to 25,and more specifically from 3 to about 20.

In addition to Bond Pattern Integrity Value and percent bond area, athird important aspect relating to the orientation and spacing of thebond elements of bond patterns is the percent offset in the longitudinaldirection 38.

Both Bond Pattern Integrity Value and percent bond area, when changed,have an immediate effect on attributes of the bond pattern 81. Howeverwith percent offset in the longitudinal direction, a change does nothave an immediate effect. However, percent offset in the longitudinaldirection does have an effect over time. As previously described, aproblem with current rotary bond patterns is “chatter” or “bounce” thatmay result when a smooth horn is pressed against a patterned anvil. This“bounce” may cause wear of the anvil, horn or support structure of therotary bond device. This wear may cause wear in the rotary bondingdevice and increased variability in bonding effectiveness. Percentoffset in the longitudinal direction addresses this problem.

The percent offset in the longitudinal direction is determined by firstmeasuring the length of a first bond element 108 (FIG. 9A) in thelongitudinal direction, as described previously herein. Second a bondelement 109 of the same size and shape is located in a differentlongitudinal row of the bond pattern. The offset is the length that thesecond bond element 109 overlaps the first bond element 108 in thelongitudinal direction divided by the length of the bond element in thelongitudinal direction. This offset is multiplied by 100 to give apercentage. FIG. 9A shows a bond pattern with 100% overlap 106 between afirst set of bond elements 100 and a second set of bond elements 102. InFIG. 9B, the first set of bond elements 100 has been offset from thesecond set of bond elements 102 by 50%, indicated by overlap 106. Offsetmay be achieved by this method of offsetting a first set from a secondset. In FIG. 9B four rows of bond elements are offset from four otherrows of bond elements, forming four pairs. Alternatively, the offsetrows need not be in separate sets. A pair of offset rows may be locatedadjacent to each other or alternatively they may be separated by one ormore rows. The rows of this pair are then no longer considered indetermining how many pairs of rows are offset. This offset reduces theamount of wear that the horn and anvil are exposed to, and thereforeprovides for less variability in bonding conditions and bond strengthover time.

Delivering the bond patterns of the present invention in absorbentarticles provide several benefits including improved fit and improvedperformance. The higher stretch of the bond patterns improve theutilization of the stretchable materials used in absorbent articles,allowing lesser quantities of materials to be used. The higher strengthsand reduced variability of the strengths of the bond patterns of thepresent invention provide improved durability to the absorbent articles.

It will be appreciated that details of the bond patterns of theinvention, given for purposes of illustration, are not to be construedas limiting the scope of this invention. Although only a few exemplaryaspects of this invention have been described in detail above, thoseskilled in the art will readily appreciate that many modifications arepossible in the exemplary aspects without materially departing from thenovel teachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention, which is defined in the following claims and all equivalentsthereto. Further, it is recognized that many aspects may be conceivedthat do not achieve all of the advantages of some aspects, particularlyof the preferred aspects, yet the absence of a particular advantageshould not be construed to necessarily mean that such an aspect isoutside the scope of the present invention.

1. A disposable absorbent article including two lateral edges, twolongitudinal edges, a front waist region, a back waist region and acrotch region interconnecting the front waist region and back waistregion, the disposable absorbent article further comprising: a bodysideliner; an outer cover; an absorbent core located between the bodysideliner and the outer cover; and an ear portion attached by a plurality ofbond elements to one longitudinal edge, wherein the bond elements form abond pattern which defines a bond pattern area and wherein the bondpattern area has a Percent Stretch of the Bond Pattern Area of from 8%to 30%.
 2. The disposable absorbent article of claim 1, wherein the bondpattern has a bond pattern edge and a Bond Pattern Integrity value offrom 0.30 to 0.60.
 3. The disposable absorbent article of claim 2,wherein the bond elements are ultrasonic bond elements.
 4. Thedisposable absorbent article of claim 2, wherein the bond elements havea circular shape.
 5. The disposable absorbent article of claim 2,wherein the bond pattern has a Bond Pattern Integrity value of from 0.35to 0.55.
 6. The disposable absorbent article of claim 2, wherein thebond pattern has a Bond Pattern Integrity value of from 0.40 to 0.55. 7.The disposable absorbent article of claim 2, wherein the bond patternhas a Bond Pattern Integrity value of from 0.45 to 0.55.
 8. Thedisposable absorbent article of claim 2, where the bond elements have abond element area of greater than 0.007585 in².
 9. The disposableabsorbent article of claim 2, where the bond pattern has a Bond elementarea of less than 0.007585 in².
 10. The disposable absorbent article ofclaim 2, where the bond elements have a bond element area less than0.00210 in².
 11. The disposable absorbent article of claim 2, where thebond pattern has a center-to-center spacing along the bond pattern edgeof greater than 0.500 in.
 12. The disposable absorbent article of claim2, where the bond pattern has a center-to-center spacing along the bondpattern edge of between 0.500-0.250 in.
 13. The disposable absorbentarticle of claim 2, where the bond pattern has a center-to-centerspacing along the bond pattern edge of less than 0.250 in.
 14. Thedisposable absorbent article of claim 1, wherein the bond elements areultrasonic bond elements.
 15. The disposable absorbent article of claim1, where the bond pattern area has a Percent Stretch of the Bond PatternArea from 10% to 20%.
 16. The disposable absorbent article of claim 1,wherein the bond pattern area has an untensioned width between 10-18 mm.17. The disposable absorbent article of claim 1, where the bond patternarea has an untensioned width between 12-16 mm.
 18. The disposableabsorbent article of claim 1, where the percent bonded area is between5% and 25%.
 19. The disposable absorbent article of claim 1, where thepercent bonded area is between 10% and 20%.
 20. The disposable absorbentarticle of claim 1, where the ear portion is also attached to thelongitudinal edge with multiple individual adhesive ribbons, wherein awidth of the individual adhesive ribbons is less than 7 mm.
 21. Adisposable absorbent article including two lateral edges, twolongitudinal edges, a front waist region, a back waist region and acrotch region interconnecting the front waist region and back waistregion, the disposable absorbent article further comprising: a bodysideliner; an outer cover; an absorbent core located between the bodysideliner and the outer cover; and an ear portion attached by a plurality ofultrasonic bonds to one longitudinal edge of the disposable absorbentarticle, wherein the ultrasonic bonds form a bond pattern and whereinthe bond pattern includes two or more pairs of longitudinal rows of bondelements, wherein the longitudinal rows of bond elements are offset inthe longitudinal direction from 30% to 70% of a longitudinal length ofan individual bond element.
 22. The disposable absorbent article ofclaim 21, wherein there are three or more pairs of longitudinal rows ofbond elements.
 23. The disposable absorbent article of claim 21, whereinthere are four or more pairs of longitudinal rows of bond elements. 24.The disposable absorbent article of claim 21, wherein there are five ormore pairs of longitudinal rows of bond elements.
 25. The disposableabsorbent article of claim 21, wherein the longitudinal rows of bondelements are offset in the longitudinal direction from 40% to 60% of alongitudinal length of an individual bond element.
 26. The disposableabsorbent article of claim 21, wherein the longitudinal rows of bondelements are offset in the longitudinal direction from 45% to 55% of alongitudinal length of an individual bond element.